In medical procedures involving a patient's heart 100, there are numerous diagnostic and therapeutic procedures that require transseptal left heart catheterization, i.e. catherization through left atrium 110 as shown in FIG. 1. The transseptal approach is an essential maneuver that provides access for both interventional cardiologists who perform antegrade mitral balloon valvuloplasty and for cardiac electrophysiologists who ablate left sided accessory pathways or perform transcatheter atrial-fibrillation therapeutic tactics.
In 15–25% of the normal healthy population, the interarterial septum (IAS) 105 has fossa ovalis or foramen ovale 107 that is patent, i.e. patent foramen ovale (PFO). The PFO is one of the three obligatory shunts in the normal fetal intrauterine blood circulation. The incidental presence of a PFO often enables a swift passage of a guide-wire across right atrium 115 and through septum 105. Pediatric cardiologists often use this route.
For procedures involving patient's already having a PFO (pre-existing hole at the fossa ovalis 107), generally a transesophageal ultrasonic probe (not shown) is inserted into the patient's mouth and placed in the esophagus. In most cases, the transesophageal ultrasonic probe is positioned approximately 30–35 cm from the mouth, i.e. in most cases positioned just above the patient's stomach.
Under transesophageal echocardiography (TEE), i.e. transesophageal ultrasonic guidance, a wire (not shown) is inserted into the right atrium 115 through an appropriate vessel such as the inferior vena cava 108 wherein the wire is guided through the fossa ovalis 107 by gently lifting the tissue flap away from the patent opening of the IAS 105 at the fossa ovalis 107. Once the wire is inserted through the fossa ovalis 107, the wire is guided to one of the pulmonary veins 116 for placement of the distal end of the wire in order to properly position and anchor the wire in the opening of the pulmonary vein 116. Accordingly, the pulmonary vein 116 has been proven to be a very reliable and steady anchoring point for the wire.
Once the wire is properly positioned in the fossa ovalis 107 and anchored in the pulmonary vein 116, a catheter sheath (“over-the-wire” type) is guided over the wire through the right atrium 115 and the fossa ovalis 107 and positioned within the left atrium 110, for instance, very close to the opening of the pulmonary vein 116.
Once the catheter sheath has been properly positioned, the wire is removed from the patient's heart 100 and other therapeutic and/or diagnostic devices are delivered through the catheter sheath. Some of these devices include implantable devices such as implantable pacemakers, electrodes, atrial septal defect (ASD) occlusion devices, etc. Accordingly, the implantable device is deliverable with typical delivery devices such as the Amplatzer® Delivery System, manufactured by AGA Medical Corporation of Golden Valley, Minn.
After placement of the catheter sheath, the implantable device is deployed from the catheter sheath within the fossa ovalis 107. Upon deployment, the implantable device is implanted into the IAS 105 thereby occluding the opening (PFO) at the fossa ovalis 107.
In all other patients, a transseptal perforation technique (anterograde approach) is necessary. However, this procedure can result in various life-threatening complications, some of which may occur because of insufficient antaomical landmarks in the heart 100. Thus, several methods have been proposed for guidance of transseptal catheterization, including transesophageal echocardiography (TEE) and intracardiac echo (ICE).
When conducting an anterograde approach with TEE, a transesophageal ultrasonic probe is positioned in the patient's esophagus as described above. Under transesophageal ultrasonic imaging guidance, an opening is made in the IAS 105 at the fossa ovalis 107 in order to facilitate and accommodate another therapeutic and/or diagnostic device. Thus, the opening is made with a penetrating device having a penetrating member such as a standard needle catheter, for example, the BRK™ Series Transseptal Needle manufactured by St. Jude Medical, Inc. of St. Paul, Minn. Accordingly, under transesophageal ultrasonic guidance, the needle catheter is initially placed in the right atrium 115 and positioned at the fossa ovalis 107. At this point, the tip of the needle of the needle catheter penetrates the fossa ovalis 107 and the catheter is inserted through the fossa ovalis 107 into the left atrium 110 through the newly created opening in the fossa ovalis 107 by the needle catheter. Once the opening in the fossa ovalis 107 is created, other therapeutic and/or diagnostic devices can be utilized.
Performing transseptal perforation safely and effectively during an anterograde approach procedure requires considerable expertise and only a minority of currently practicing physicians are performing this type of procedure on a regular, routine basis. In fact, many electrophysiologists are refraining from performing transseptal procedures because of lack of skill and unavailable guidance.
Up till now, there have been no devices or methods that can allow a physician to efficiently perform a transseptal facilitation or perforation procedure in an effective manner.